Rating of the industrial application potential of yeast strains by molecular characterization

Each brewing yeast has its own unique impact on the formation of aroma compounds, and thus, on the properties of the final beer. The selection of the perfect strain for a specific brewing process results from physiological properties, which can be elucidated in brewing experiments. These properties result from genetic and proteomic features of each yeast strain. In the current study, 23 blind-coded yeasts were analyzed on a genomic level by microsatellite genotyping at 13 loci, on a sub-proteome level by MALDI-TOF MS, and on their phenotypic property by phenolic off flavor (POF) production assessment. These results were compared with the current application profile of each yeast strain. An expanded MALDI-TOF MS database was used to identify the blind-coded samples on species level, which was achieved to 100%. The samples belonged to top-fermenting Saccharomyces (S.) cerevisiae, bottom-fermenting S. pastorianus and S. cerevisiae var. diastaticus. Different groupings below species level were found with microsatellite analyses (classification on strain level) and MALDI sub-proteome (subdivision of yeasts into groups), which provided a prediction of application potential to beer styles for which they are currently used. The test for POF showed a wide variation and appears to be a strain-dependent property. However, this could serve as a starting point for the classification of yeast strains with respect to their usefulness for the production of specific beer styles or non-brewing applications.